The other location was the railroad museum at Bowie MD. This comprises the old PRR BOWIE tower and a PRR caboose. The tower was moved about 200 feet from its old location after Amtrak closed it in the 1980's and has been a museum ever since. I also took a walk around the Pope's Creek wye where the Pope's Creek Secondary branches off the NEC. This line has three coal fired power plants on it as well as local freight customers and sees a fair amount of traffic. Coal trains are brought up from the south although I do thing some traffic does come down from the north, but that is limited due to the tunnels in Baltimore City. The wye has an Amtrak substation in the middle of it and BOWIE is still an active Amtrak interlocking.
Finally I went up the road to take a picture of the PRR Position Light approach signal to BOWIE. It was a fixed aspect displaying Caution.
Full set of pictures are here:
Here is a view of the meat of the current West Baltimore interlocking. Old Main Line ran to the left to where the B&O museum is today. New Main Line curves off to the right toward Camden Yards and the Baltimore Belt Line. The far right track is not part of the interlocking.